Hollow mortising chisel



' Feb.26,1935.. H E, TAUTZ 1,992,726

v wig-MESSE@ :f1

HOLLOW MORTISING CHIASEL Filed sept. 15, 1934 .F.zjG. i

' IG.' ITICLZ K A Patented Feb. 2,6, 1935 'UNITED STATE PATENT oF'Flcl;l

'latam HOLLOW MOBTISING CHISEL Herbert E. Tautz, Milwaukee, Wis., assignor to The Delta Manufacturing Company, kee, Wis., a corporation of Wisconsin Milwau- Appucm'on september 15, -1934, serai No. 144,153

l 4 Chim. The invention relates to hollow "mortising chisels of the type having a longitudinal opening for receiving a rotatable bit.

It has heretofore been customary to construct.

vide a durable but inexpensive hollow mortising chisel of composite construction in which the amount of edge-retaining steel is greatly reduced Vwithout impairing strength'and cutting qualities, 5, and in which the parts are rigidly and accurately lsecured together in a simple but effective manner, the' construction being of such character as to facilitate manufacture and to reduce waste of material. v The invention further consists in the several features hereinafter described and claimed.

One specic lembodiment of the invention is shown in the accompanyingdrawing, in which Fig-1 is a side view off. a hollow mortising chisel l constructed in accordance with the invention:

Fig. 2 is a longitudinal sectional view of the l chisel, parts being broken-away;

Fig. 3 is a view ofthe cutting member A shankbeforetheyaresecuredtogethentheshankv D beinsshowninlongitudinalsection;

` iisatransverse sectionalviewtakenon thelineHofIfig. 1. and y `IIs.151satransverse'sectionalviewtakenon Thecuttingmemberorbaridisformedofa l ablyhish-carbonitool 'Letters Patent is:

a'*" a geen are preferably broken or chamfered at 19'along the end portion of the bar ntting in the bore 15.

The hollow cutting bar 10 is provided in itsI side edges with notches to register with the reduced annular end portion 16 of the conical head 16, the notchesbeing conveniently formed by a turning operation.

, In assembling the device, .the chamfered end 'of the cutting bar 1o is pressed into the bore-15 of the shank 1l `until the4 bar abuts against a lo shoulder 21 formed at the inner end of thelbore. The close nt of the parts holds them in axial alignment. The parts are then' secured rigidly together by pressing the annular outer endvportion 16'. of the conical-head 16 inwardly into the 15 notches 20 of the chisel bar, as seen in Fig. 2, and inwardly against the flat sides of the cutting bar, as seen in Figs. 1 and 4. 'The pressing operation may be eiiected by means of asuitable tool o r die 22. zo

When the chisel is in use, it co-oper'ates in the usual manner with a rotary bitv 23 (Figf) which passes through it, the chisel being held against rotation by clamping its stem 17 in any 4suitable manner. The cutting member or -barjlo can be economicaliy formed from tool steel bar stock of square.

cross-section, there being butiittle waste. The somewhat larger shank 11 can be economicallyd formed from inexpensive metal,.such as low-car- A bon steel, by a simple turning operation.

What I-claim as newand desire tosecure by v 1. A mortising chisel comprising a hollow'bar of edge-retaining metal havinga chisel edge at one end and recessed outer si'cleiwalls djacents maidrecessedsidewallsofthebar." 2. A mortising chisel comprising a hollow bar ofsquare cross-section formed of edge-retaining adjacent the other. end formed in hollow shank of softer metal having a head provided with a`bore tightly receiving the notched end portion of said bar, said head having an inwardly pressed annular .edge portion of reduced `thickness adjacent the outer end -of said bore, said reduced edge portion projecting into and engaging the notched portion of said bar.

4. A mortising chisel comprising a.v hollow bar of square cross-section formed of edgeretaining metal and having a chisel edgeat one end, and a hollow shank of softer metal having a substantially cylindrical bore tightly receiving the other end of said bar and having inwardly pressed side walls engaging the side faces of said bar.'

HERBERT E. TA'UTZ. 

